Recovery of acetone and phenol from cumene hydroperoxide decomposition product



United States Patent RECDYERY 0F ACETONE AND PHENOL .EROM

CUMENE .HYDROPEROXIDE. DECOMPOSITION PRODUCT,

Application October 14, I954, Serial No. 462,146-

3, Claims. (Cl. 202939) Thisrinventionwrelates ctoan improved method for recoyeri jgssubstantiall'y pure phenol and acetone from the crudewreactiohzproduct, obtained by decomposing -:cun1ene hydroperoxide =in,-the:-.presence of an acid catalyst and isatcontinuation-inepart of copending application Serial No. 281,212,, v:filedApril 8, 195 2;

Agrecently developed :process provides a means for manufacturingsphenoljandacetone from icumene; In the practice of, the process cumeneis-ox'idized in liquid phase-witha;freeyoxygemcontaining gas, usually air, at temperatures from .about 7.195 to 240 ,F. in the presence of an alkaline-material-to stabilize the hydrop'eroxide product. ,The oxidation reaction product consist-s predominantlyof cumene-and cumene-,hydroperoxide; ordinarily,.it has a cumenehydroperoxide-content in the range from about [2.5 to 357% by weight, and contains minor amountsof impurities and side reaction productsinclud- 'ing fiime'thylphenyl carbiildl, ,acetophenone, alpho-methyl styrene, cumyl'phenol, and salts of "lower aliphatic acids. Substantiallyall of thjeunr'eacted'cu'menejis removed .from the'crude-oxidation reaction product by vacuum distillation to producea cumene hydroperoxide concentrate substantially-' free of-cumene-and having a cumene hydroperoxide"contentof about 90% by weight; The cumene hydroperoxideconcentrate is :then contacted with a small amountof a:strong acid catalyst at temperatures in the ranget-fromabout 150 to 350*F..- to cause cleavage of the cumene ;hydroperoxidemolecules forming phenol and acetone.., The cumene hy droperoxide decomposition is esirably conducted in .thepresence --of a volatile inert diluent conveniently acetone, which is refluxed during the decomposition step. to facilitate temperature, control, since the decomposition reaction ,is exothermic, The decomposition reaction product contains many phenol and acetone and a-minorproportionof organic'by;productsjin cluding'acetophenon'e; 'dimethylp'henyl carbindl, alphamethyl styrene, -cumyl phenol, 'acetaldehyde, 'mesityl' ox ide, some-higher boiling apparently polymeric materials, the acid catalyst, andorganic acidic contaminants *formed during the oxidation stepan'd/.orduring thecumene hydroperxide decomposition step. Sulphuric acid-is ordinarily employed to catalyze the decomposition of cumene hydroperoxide, but other acids such as formic acid, phosphoric acid, para-toluene sulfonic acid,,an d the like, may be employed for this purpose.

When the. cumene hydroperoxide decomposition is .complete, the acid catalyst is neutralized with any con venient basic material such as sodium hydroxide, sodium carbonate, sodium phenolate,jandjthejlike. The .neu-

tralized decompositiomreaction mixture contains the 'desired phenoland acetoneproducts, in a complexmixture whichincludes-not only the organic impurities ofthe character indicated above, buttalso the saltsproduced :during neutralizationof the cleavage product. Economic f recovery of v phenol and acetone .at purities. meeting com-- mercial specificationsfrom-such-mixtures isnosimple'matter. Attempts :to l'jel'rto've the. saltsiormedduring neutrali zation -by filtrationlare ionly. partiallysuccessful, and-ordi- Ice narily about-'25 %-'of-the total salt "contained "inthe crude product remains in --the--fi1trate. When "such a salt-com taining filtrateis subjected 'to fractional distillation to separate the individual organiccomponents of the mixture, the salts tend to crystallize, plugging transfer lines and fouling heatexchan-gers and reboilers. Further, if the salt removal is incomplete, as it'necessarily is following filtration, sodium carboxylates contained in the -filtrate decompose 1 during distillation, causing serious corrosion of dist-illa'tionequipment. While most of the orga'nic impurities'con'tained in-the cumene hydroperoxide decomposition product can be separated by fractional distillation, hydrocarbon oils, such as alpha-methyl-styrene, which boil'closeto the boiling point of phenol, and :mesityl oxide, especiallythe latter, are extremely difficultto separate.

lit has now been found-that the difliculties inherent in the recovery of substantially- 'purephenol and substantially pure ace"tone from the cumene hydroperoxide decomposition-reaction mixture can be expeditiously and inexpensively met by:-addi'ng a substantial quantity of water to the cumene hydroperoxide decomposition mix- :ture, settling theresultant mixture to separate an organic phase and an aqueous phase, and-subjecting both phases to fractional distillation.

in :azpreferred embodiment of the invention, the eumene :hydroperoxide decomposition product is intimately mixed with 025- 10 .B times :its Weight of water, and the acid catalyst-is neutralizedin awvashing and neutralizat-ion zone. The JneutralIrniXture is 'settled to' separate a water phase and an organic :phase. The water phase is fractionally, distilled to separate an overhead fraction consisting-predominantlyofwater and containing minor proportions ofephenol and acetone'and a bottoms fraction consisting: essentiallyzo'f water containing in solution salts formed during neutralization. The overhead fraction is returned to the washing :and neutralizing zone and the bottoms:fractiondsdiscarded: The organicphase is fractionallyrudistilled'. to separate .an overhead fraction consisting; predominantlyrof acetone and having a substantial content ofwater and "a bottoms fraction consisting predominantlymofphenol. The .latter overhead fraction is; distilled tmseparate a- ;further "overhead 1 fraction consisting-of essentiallypure1acetone and a bottoms fraction consisting predominantly-of:water-and containing "a minor proportion of: phenol. This bottoms fraction 'is; mixed withffresh water. and .the mixture is settled to-separate an upper orgatiicphaseenda loweraqueous phase conta'ining dissolvedrphenol and theaqueous phase,-is re turned to the washing and neutralizing zone.

The 'ap'pended'drawing is a blockffiow diagram {illustra'ting a process-flow suitable for the practice of the invention. "In a representative operation of the process, a cumen'e hydroperoxide decomposition product containing .2% by weight of acetaldehyde, 45.5% by weight of acetone, 1.4% by weight of water, 38% by weight of phenol, 1.25 by weight .of mesityl oxide, less than 1% by Weight:of,cumenc, .6% by Weight ofsulfuric acid, and

the remainder; hydrocarbons including alpha-methyl styrene, dimethylph'enyl' carbinol, acetophenohe, cumyl and alower aqueous phase. "The aqueous phase is passed through line into line 1. The aqueous phase formed in washer and neutralizer 3 is withdrawn through line 11 and passed into still 12. In still 12 an overhead fraction comprising water and substantially all of the phenol and acetone contained in the aqueous phase is removed overhead through line 13 and passed into Water storage tank 8. A bottoms fraction comprising water substantially free of organic material and containing dissolved sodium sulfate is removed through line 14. The organic phase formed in washer 7 is withdrawn through line 15 and passed into distillation zone 16 in which it is fractionally distilled to separate an overhead fraction containing water, a minor proportion of phenol and substantially all of the acetone contained in the organic phase which is removed overhead through line 17 and passed into stripping zone 18. In stripping zone 18 a minor overhead fraction containing substantially all of the acetaldehyde contained in the feed is removed through line 19. The bottoms fraction from stripping zone 18 comprising acetone, water and minor proportions of phenol and mesityl oxide is withdrawn from stripping zone 18 through line 20 and passed into acetone still 21. Dry acetone is removed overhead from still 21 through line 22. A second overhead fraction consisting essentially of acetone, but containing from 0.5 to 5% water, is removed from distillation zone 21 through line 23. The bottoms fraction from distillation zone 21 comprising water, phenol and mesityl oxide is withdrawn through line 24 and passed into extraction zone 25. The bottoms fraction from distillation zone 16 comprising phenol, water and organic impurities is removed through line 26 and passed into distillation zone 27. In distillation zone 27 an overhead fraction comprising phenol, water and minor proportions of organic impurities is removed through line 28 and passed into distillation zone 29. A heavy bottoms fraction comprising higher boiling organic materials and a minor proportion of phenol is removed from distillation zone 27 through line 30. This bottoms fraction may be extracted with'caustic, if desired, to recover phenol. In distillation zone 29 a minor low boiling overhead fraction comprising water, hydrocarbon impurities and phenol is removed and passed through line 31 into extraction zone 25. A bottoms fraction separated in distillation zone 29 is passed through line 32 into distillation zone 33. Substantially pure phenol is recovered as the overhead fraction in distillation zone 33 through line 34. A minor bottoms fraction is separated in distillation zone 33 and passed through line 35 into either distillation zone 16 or distillation zone 27, as desired. Fresh water is introduced into extraction zone through line 36 into line 24 and then into extraction zone 25.

The mixture in extraction zone 25 is settled to separate an upper organic phase consisting mainly of organic impurities and containing a minor proportion of phenol which is removed through line 37. A lower aqueous phase formed in extraction zone 25 consisting principally of water containing dissolved phenol is removed through line 38 and passed into water storage tank 8.

Pursuant to the operation in the manner above described, substantially complete recovery of the phenol and acetone contained in the cumene hydroperoxide decomposition mixture is accomplished and both products are recovered at high purities and meet the most rigorous commercial specifications. The only waste water discharged from the system is the water containing dissolved salt Which is discharged through line 14; this Water is substantially completely free of phenol and presents no disposal problem. Products recovered other than specification phenol and specification acetone are the heavy bottoms fraction removed from distillation zone 27 through line 30, the organic phase removed from extraction zone 25 through line 37, the minor acetaldehyde fraction removed from acetaldehyde stripper 18 through line 19 and the Wet acetone stream removed from distillation zone 21 through line 23. The bottoms fraction recovered at line and the organic fraction recovered at line 37 may be processed for recovery of phenol and organic by-products, if desired, or they may be burned. The minor acetaldehyde stream recovered at line 19 can be processed for the recovery of acetaldehyde, if desired, or used as fuel. The wet acetone stream recovered through line 23 is desirably employed as the inert diluent in the cumene hydroperoxide decomposition reaction, but may be subjected to further fractional distillation for the recovery of specification acetone, if desired.

The employment of the above-described water system in the separation of the crude cumene hydroperoxide decomposition product efiectively removes all salts produced during neutralization of the decomposition mixture and eliminates the problems which attend any attempt to subject the salt-containing product to fractional distillation. The substantial water content of the feed to distillation zone 16 permits substantially complete removal of the difficultly separable mesityl oxide impurity in the overhead from that distillation zone. Further, the employment of water in the manner described permits substantially complete removal of hydrocarbon impurities boiling close to the boiling point of phenol in the overheads from distillation zones 16 and 29. Substantially complete removal of these hydrocarbon materials is required if specification grade phenol is to be produced.

The process described above has been studied in large scale operation over an extended period. It has been found that dilution of the cumene hydroperoxide decomposition mixture with from 2.5 to about 3.0 times its weight of water followed by processing in the manner described above permits substantially complete recovery of the phenol and acetone contained in the mixture at specification purity. Representative compositions of significant streams in the process flow described above are shown in the following Table I.

TABLE I Composition per cent by weight 11.0 Phenol Acetone fig ggggg Gumene g gg igfggg Carbinol gggg} His 0. Salt Heavier While the compositions above shown are representative, it should be recognized that some variations in composition will be encountered in commercial practice. The hydrocarbon impurities may be expected to increase markedly if the cumene feed has an appreciable content of butyl benzene or of ethyl benzene. In commercial practice, the content of these materials in the cumene feed may vary considerably. The content of oxygenated impurities will vary somewhat with the conditions under which the oxidation reaction is conducted and with the degree of conversion of cumene to cumene hydroperoxide which is accomplished prior to concentration of the cumene hydroperoxide. The content of oxygenated impurities will also vary somewhat with the conditions under which the decomposition of the cumene hydroperoxide is conducted. The employment of higher temperatures in the decomposition reaction may be expected to increase the content of the oxygenated impurities in the crude product and the mesityl oxide content of the decomposition mixture increases appreciably as the quantity of acid catalyst employed in the decomposition reaction is increased.

Representative flow rates in the more significant transfer lines employed in the process are shown in the following Table II.

TABLE II Parts by weight per hour Line 1 242 Line 4 5 8 Line 9 214 Line 19 0.8 Line 22 55 Line 23 56 Line 24 49 Line 35 21 Line 36 25 Line 30 20.5 Line 31 (top) 29 Line 33 94 Line 14 87 We claim:

1. A process for recovering substantially pure phenol and substantially pure acetone from the reaction product mixture produced by catalytically decomposing cumene hydroperoxide concentrate which is substantially free of cumene in the presence of an acid catalyst, which comprises neutralizing the reaction product and intimately mixing it with 0.25 to 3 times its weight of water in a neutralizing and washing zone, settling the resultant mixture to separate a water phaseand an organic phase, fractionally distilling the water phase to separate an overhead fraction consisting predominantly of water and containing minor proportions of phenol and acetone and a bottoms fraction consisting essentially of water containing in solution salts formed during neutralization, returning the overhead fraction to the washing and neutralizing zone and rejecting the bottoms fraction from the system, fractionally distilling the organic phase to separate an overhead fraction consisting predominantly of acetone and having a substantial content of water and a bottoms fraction consisting predominantly of phenol, fractionally distilling the last named overhead fraction to separate a further overhead fraction consisting of essentially pure acetone and a bottoms fraction consisting predominantly of water and containing a minor proportion of phenol, mixing the bottoms fraction with fresh water and settling the mixture to separate an upper organic phase and a lower aqueous phase containing dissolved phenol and passing the aqueous phase into the washing and neutralizing zone.

2. A process for recovering substantially pure phenol and substantially pure acetone from the reaction product mixture produced by catalytically decomposing cumene hydroperoxide concentrate which is substantially free of cumene in the presence of an acid catalyst, which comprises neutralizing the reaction product and intimately mixing it with 0.25 to 3 times its weight of water in a neutralizing and washing zone, settling the resultant mixture to separate a water phase and an organic phase, fractionally distilling the water phase in a first distillation zone to separate an overhead fraction consisting predominantly of water and containing minor proportions of phenol and acetone and a bottoms fraction consisting essentially of water containing in solution salts formed during neutralization, returning the overhead fraction to the washing and neutralizing zone and rejecting the bottoms fraction from the system, fractionally distilling the organic phase in a second distillation zone to separate an overhead fraction consisting predominantly of acetone and having a substantial content of water and a bottoms fraction consisting predominantly of phenol, fractionally distilling the overhead fraction from the second distillation zone in a third distillation zone to separate an overhead fraction consisting of essentially pure acetone and a bottoms fraction consisting predominantly of water and containing a minor proportion of phenol, mixing the bottoms fraction from the third distillation zone with fresh water in an extraction zone and settling the mixture to separate an upper organic phase and a lower aqueous phase containing dissolved phenol and passing the aqueous phase into the Washing and neutralizing zone, fractionally distilling the bottoms from the second distillation zone in a fourth distillation zone to separate a minor overhead fraction comprising water and phenol and passing the overhead fraction from the fourth distillation zone into the extraction zone.

3. A process for recovering substantially pure phenol and substantially pure acetone from the reaction product mixture produced by catalytically decomposing cumene hydroperoxide concentrate which is substantially free of cumene in the presence of an acid catalyst, which comprises neutralizing the reaction product and intimately mixing it with 0.25 to 3 times its weight of water in a neutralizing and washing zone, settling the resultant mixture to separate a water phase and an organic phase, fractionally distilling the water phase in a first distillation zone to separate an overhead fraction consisting predominantly of water and containing minor proportions of phenol and acetone and a bottoms fraction consisting essentially of water containing in solution salts formed during neutralization, returning the overhead fraction to the washing and neutralizing zone and rejecting the bottoms fraction from the system, fractionally distilling the organic phase in a second distillation zone to separate an overhead fraction consisting predominantly of acetone and having a substantial content of water and a bottoms fraction consisting predominantly of phenol, fractionally distilling the overhead fraction from the second distillation zone in a third distillation zone to separate an overhead fraction consisting of essentially pure acetone and a bottoms fraction consisting predominantly of water and containing a minor proportion of phenol, fractionally distilling the bottoms from the second distillation zone in a fourth distillation zone to separate a minor overhead fraction comprising water and phenol, mixing the bottoms fraction from the third distillation zone and the overhead fraction from the fourth distillation zone with fresh water in an extraction zone and settling the mixture to separate an upper organic phase and a lower aqueous phase containing dissolved phenol and passing the aqueous phase into the washing and neutralizing zone.

No references cited. 

1. A PROCESS FOR RECOVERING SUBSTANTIALLY PURE PHENOL AND SUBSTANTIALLY PURE ACETONE FROM THE REACTION PRODUCT MIXTURE PRODUCED BY CATALYTICALLY DECOMPOSING CUMENE HYDROPEROXIDE CONCENTRATE WHICH IS SUBSTANTIALLY FREE OF CUMENE IN THE PRESENCE OF AN ACID CATALYST, WHICH COMPRISES NEUTRALIZING THE REACTION PRODUCT AND INTIMATELY MIXING IT WITH 0.25 TO 3 TIMES ITS WEIGHT OF WATER IN A NEUTRALIZING AND WASHING ZONE, SETTLING THE RESULTANT MIXTURE TO SEPARATE A WATER AND AN ORGANIC PHASE, FRACTIONALLY DISTILLING THE WATER PHASE TO SEPARATE AN OVERHEAD FRACTION CONSISTING PREDOMINANTLY OF WATER AND CONTAINING MINOR PROPORTIONS OF PHENOL AND ACETONE AND A BOTTOMS FRACTION CONSISTING ESSENTIALLY OF WATER CONTAINING IN SOLUTION SALTS FORMED DURING NEUTRALIZATION, RETURNING THE OVERHEAD FRACTION TO THE WASHING AND NEUTRALIZING ZONE AND REJECTING THE BOTTOMS FRACTION FROM THE SYSTEM, FRACTIONALLY DISTILLING THE ORGANIC PHASE TO SEPARATE ON OVERHEAD FRACTION CONSISTING PREDOMINANTLY OF ACETONE AND HAVING A SUBSTANTIAL CONTENT OF WATER AND A BOTTOMS FRACTION CONSISTING PREDOMINANTLY OF PHENOL, FRACTIONALLY DISTILLING THE LAST NAMED OVERHEAD FRACTION TO SEPARATE A FURTHER OVERHEAD FRACTION CONSISTING OF ESSENTIALLY PURE ACETONE AND A BOTTOMS FRACTION CONSISTING PREDOMINANTLY OF WATER AND CONTAINING A MINOR PROPORTION OF PHENOL, MIXING THE BOTTOMS FRACTION WITH FRESH WATER AND SETTLING THE MIXTURE TO SEPARATE AN UPPER ORGANIC PHASE AND A LOWER AQUEOUS PHASE CONTAINING DISSOLVED PHENOL AND PASSING THE AQUEOUS PHASE INTO THE WASHING AND NEUTRALIZING ZONE. 